1. Field
The following description relates to a semiconductor device and a corresponding manufacturing method for the semiconductor device. For example, the semiconductor device includes high voltage field effect transistor and a JFET. The following description also relates to a semiconductor device and a manufacture method thereof with a junction transistor configured to control a pinch-off voltage and current.
2. Description of Related Art
A high voltage transistor is a device controlling passage of power having tens to hundreds of voltage associated with the power and performs switching of such a high voltage power. The high voltage transistor may include a high voltage Vbd that does not cause a breakdown to block a current in a turned-off status and may also include a small on-resistance Rsp value to reduce power loss in a turned-on status.
A junction field effect transistor (JFET) is a device included in such a controller of a high voltage power with the high voltage transistor. Further, the JFET may supply a start-up power to a circuit that controls a gate of the high voltage transistor. Generally, the circuit configured to control the gate of the high voltage transistor includes low voltage transistors, and thereby the junction transistor restricts a voltage and a current that are applied to the circuit so that they are not able to exceed a threshold through a pinch-off.
A high voltage transistor and a junction transistor according to an alternative approach use a substantial area to perform the aforementioned features. Accordingly, the high voltage transistor and the junction transistor have difficulties in minimization of size.
In an effort to solve the afore-mentioned problem an alternative approach uses a feature relating to a manufacturing method of a high voltage transistor including a high voltage transistor combined with a junction transistor. An on-resistance Rsp value may be reduced because an opposite conductivity type buried impurity layer is included in a drift drain region of a high voltage transistor of the above features.
However, the junction transistor of the above features uses a deep-well region that is used as a drift drain region of a high voltage transistor as a channel region of the junction transistor. Herein, a doping concentration of the deep-well region is determined according to the on-resistance Rsp of the high voltage transistor and a structure of a buried impurity layer is determined appropriately. Accordingly, the junction transistor of the above feature includes a channel region that is determined according to an electric feature of a high voltage transistor. Thus, there is an issue that respective control of current-voltage of the junction transistor is difficult.